Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of anionic (negatively charged) groups on the surface of retinal pigment epithelial cells (RPE), rod photoreceptor cells (RP) and discarded rod outer segments (R0S) was studied by labeling these groups with cationic ferritin (CF) at different pH values. In normal neonatal rats, characteristic CF binding patterns were observed on the RPE cell surface at pH values ranging from 1.8-7.2. Similar distributions were seen on the surface of RPE cells from RCS-p+ rats with inherited retinal degeneration. Treatment of RPE cells from normal neonates with several different degradative enzyme preparations prior to CF labeling, did not alter the density or distribution of CF molecules at any of the pH values tested. In normal adult rats, CF binding to RPE cells was essentially similar to that observed in neonates. In RP cells, heavy CF labeling at pH 1.8 was seen on the surface of the inner and outer segments and connecting cilium. CF labeling patterns on discarded R0S undergoing phagocytosis were similar to those on RPE cells at all pH values except pH 5.5. The findings indicate that anionic sites are present on the surface of RPE and RP cells and on discarded R0S undergoing phagocytosis. There is no evidence that such sites are involved in the phagocytic defect characteristic of RCS-p+ rats. Adult-like patterns of anionic sites on RPE cells appear early in postnatal development; their resistance to a wide range of degradative enzymes suggests that the carbohydrates or proteins containing these anionic moieties are organized in a complex fashion in the RPE cell surface.
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PMID:Distribution of anionic sites on the surface of retinal pigment epithelial and rod photoreceptor cells. 731 91

A breakdown in the blood-retinal barrier to certain proteins is described in mutant RCS rats with inherited retinal degeneration. Intravenously injected microperoxidase and horseradish peroxidase are extravasated from the outer (but not inner) retinal capillaries of these rats, at approximately 11 weeks of age and older. The number of affected capillaries increases with the age of the animals and progression of the retinal dystrophy until virtually all capillaries in the outer retina become permeable to these tracers. In such capillaries, enzyme reaction product is demonstrable in a greater proportion of luminal vesicles and in the majority of abluminal vesicles. Reaction product is also localized in cytoplasmic vacuoles, the basal laminae of endothelial cells and pericytes, and the perivascular spaces. The increased permeability of outer retinal capillaries in RCS rats appears to be due to an increase in transendothelial vesicular transport of the probe molecules. There was no evidence that either tracer permeated the interendothelial junctions or entered the basal laminae by reflux from the perivascular spaces. It is suggested that factors originating from the degenerated photoreceptor cells may play a role in stimulating the vesicular transport observed in permeable capillaries. In contrast to these findings, the outer retinal capillaries of RCS rats were not permeable to hemoglobin, catalase, or ferritin, regardless of the age of the animal or the degree of retinal degeneration. Since the vesicles that form at the luminal front are covered by a diaphragm, it is possible that this structure prevents entry of these larger proteins into the endothelial vesicle, even in capillaries that are demonstrably permeable to the smaller tracers.
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PMID:Breakdown of blood. Retinal barrier in RCS rats with inherited retinal degeneration. 742 Nov 23